The invention relates to a single-lens relfex camera which, for the purpose of exposure measurement in the path of the taking rays with the diaphragm open, is provided with an adjusting device capable of being connected to a coupling element of the diaphragm stop adjuster on the lens side and movable in opposition to its restoring spring in accordance with the diaphragm values to which the diaphragm detent setting device can be adjusted.
Exposure measuring devices are known which are built into single-lens reflex cameras and which provide the desired measuring result by an internal measuring operation with an open diaphragm. This necessitates special lens units having coupling elements which are adapted to the exposure measuring device on the camera side and which are connected with the diaphragm detent setting device on the lens side. The camera can likewise be fitted with interchangeable objectives having no such coupling elements and suitable for taking photographs, but no exposure measurement is possible. In view of this, known cameras have detent devices by which the restoring movement of the adjusting device of the exposure meter is limited to a position corresponding to the maximum diaphragm aperture. A detent device of this kind enables exposure measurement to be effected with the diaphragm in the operating position.
On the removal of the interchangeable objective the adjusting device remains in the position corresponding to the said operating diaphragm.
Further known means adopted for exposure measurements with the diaphragm in the operating position consist of interchangeable objectives each of which has a rigid control element which is operative independent of the diaphragm setting device and by which, when the interchangeable objective is mounted, the adjusting device of the exposure meter can be held, in opposition to the force of its restoring spring, in the initial position corresponding to the maximum diaphragm aperture. The camera itself does not have to be fitted with any detent devices for measurement with operating diaphragm. When these interchangeable objectives are removed the adjusting device is moved by its restoring spring into a basic position which differs from the position corresponding to the initial diaphragm.
The purpose of the invention is to simplify the structure of the camera still further.